Ultra-High Resolution Optical Coherence Tomography (OCT) provides 2D and 3D virtual cross-sectional images of an object in a non-invasive and non-contact way. It is suitable for the investigation of translucent and transparent materials (e.g. varnishes, glass, glazes) in the near-infrared (central wavelength 810 nm).

OCT is a fast and efficient technique for the collection of 2D and/or 3D measurements of an objects surface and subsurface structures at a resolution of a few microns. The technique requires objects to be at least semi-transparent to near infrared radiation, making it well suited to investigating materials such as varnishes, paint glazes, some paint layers, glazes on ceramics and faience, jade, historic glass and enamels, amber, rock art, parchment and paper. The 2D cross sectional images obtained by OCT are usually presented as cross-sectional views, similar to microscopic images of sample cross-sections extracted from the object. If necessary, 3D information of an entire volume (a cube) may be collected by combining a sequence of up to 1000 cross-sections across the surface. The ultra-high resolution OCT at 810 nm is optimised to maximise axial resolution for measurements of surface and subsurface transparent and semi-transparent structures, producing a resolution of approximately 1 micron in varnish and paint. The major advantages of OCT are the ability to see the layers and microstructure at and below the object surface in a non-contact and non-invasive manner (intensity of light used for examination is in the order of a milliwatt), and the rapid speed of data collection with no need for object preparation. The speed of data collection and online imaging makes the technique also ideal for monitoring dynamic processes where stratigraphy is likely to alter, for example during conservation treatment. Given the non-invasive nature of the technique, the number of measurements across the entire surface can be unlimited, making it possible to have a representative view of the whole object.

The system is restricted to indoor environments and requires a 230 V power supply to function.